Grinding-mill



W. N, o-oscmovfi.

Grinding Mill.

No. 238,859. Patented March 15.1881.-

N.PEFERS. PHQTO-UTMOGRAPHER, WASHINGTONUDLC.

UNITED STATES PATENT @FFICE.

WILLIAM N. GOSGROVE, OF FABIBAULT, MINNESOTA.

GRINDING-MILL.

SPECIFICATION forming part of Letters Patent No. 238,859, dated March15, 1881.

Application filed February 4, 1880. v

To all whom it may concern Be it known that I, WILLIAM N. OOSGROVE, ofFaribault, in the county of Rice and State of Minnesota, have inventedcertain new and useful Improvements in Machinery for Man ufacturingFlour and I do hereby deelare the following to be a full, clear, andexact description of the same, reference being had to the accompanyingdrawings, forming part of this specification, in which- Figure 1represents a longitudinal vertical section of the mill, taken on theline mm, Fig. 2. Fig. 2 is a top-plan view of the same, and Fig. 3 atransverse section of the grinding-cylinder.

Similar letters of reference in the several figures denote the sameparts.

This invention relates to certain improvements in that class ofgrinding-mills in which the material is ground between a verticalrotating grinding-cylinder or runner and a stationary concave.

Theinvention consists, primarily, in the combinatioinwith a rotatinggrinding-cylinder, of a concave havingits inner face composed ofalternate grinding-surfaces and screen-sections, and capable ofadjustment so that each succeediu g grindin g-surface shall approachnearer to the face of the grindingcylinder than its predecessor, wherebythe material is enabled to be subjected to a reduction more or lessgradual, and the fine flour and middlin gs screened off as fast as made.

It further consists of a hollow rotating grinding cylinder havingapertures in its sides through which to take air, and openings in itsperiphery or grinding-surface through which to force out, by therotation of the cylinder, .the air so supplied.

It further consists in constructing the grind: ing cylinder of two sideplates or circular flanges secured to an arbor and lands orgrindingsurfaces secured between the side plates, or to the peripheriesthereof, with spaces between the lands for the escape of air forced outfrom within the cylinder.

It further consists in the combination of a hollow rotatinggrinding-cylinder, having openings in its periphery for the escape ofair, with a concave composed of alternate grinding-surfaces andscreen-sections, whereby the air escaping from the grinding cylinderassists in bolting the fine flour and middlings through the screen-sections of the concave as fast as made. i

In the drawings, A represents the frame of a vertical grinding-mill B,the rotating cylinder or runner; O, the concave, andD the hopper intowhich the grain to be ground is placed,

the concave is connected to the cross-head con-,

sist of two screws, cc, which pass through the upper part of thecross-head, and are secured to the back of the concave on opposite sidesof a plane drawn through the vertical center of the latter, and a thirdscrew, 0, which passes through the lower part of the cross-head, and issecured to the back of the lower part of the concave at or near thevertical center thereof.

By means of nuts {1 g 9, working on the screws 6 e e on opposite sidesof the crosshead, the concave can be adjusted as desired with respect tothe face of the rotating grinding-cylinder, and held firmly and securelyin its adjusted position. Side ears .orlugs, b b, are provided on theconcave, through which vertical screws h h pass and bear upon the top ofthe cross-head. When it becomes necessary to take the concave out ofwind or adjust it sidewise, it can be done by loosening one of thesescrews h and tightening the other.

The interior of the concave is preferably made hollow, as shown in Fig.1, and its face,

or that part next the grinding-cylinder, is com posed ofgrindingsurfaces or lands 1 l and screen-sections s 8, arrangedalternately, so that the fine flour and middlings made by the firstlands are screened out through the first screensection, while theremaining material passing to the next land is still further reduced andthe resulting fine flour and middlings screened out through the secondscreen-section, and so on throughout the extent of the concave. Thegrinding-surfaces or lands of the concave may be dressed or prepared inany preferred manpart of the concave shall be closer to the face of thecylinder than the upper part. The grain, being fed from the hopper inbetween the rotating cylinder and the concave in the usual manner, issubjected to the action of the cylinder and the first grinding-surfaceor land of the concave, and the line fiour'and middlings by them madeare screened out through the first screen-section, the remainingmaterials being then subjected to further reduction by the secondgrinding-surfaces, and the resulting fine flour and middlings screenedout through the second screen-section, and so on throughout the extentof the concave, the fine flour and middlings being screened off as fastas made, and the remainingmaterial subjected to a gradual reductionwithout intermitting the operation of the grinding cylinder or stone.The screens may all be of the same grade or of different grades, and thefiour and middlings screened out through them may mingle in the interiorof the hollon concave and be carried off in a mass; or, as shown in thedrawings, partitions p 19 may be provided within the concave between thevarious screens, and the flour and lniddlin gs passed by each screenkept separate andapart from that passed by the others. The properadjustment of the concave to the cylinder will be determined by thequality of the grain operated upon, the grade of flour to be made, andother circumstances.

The rotating cylinder or runner used in connection with my improvedconcave may consist of a solid or a sectional stone, or may be of anyother well-known construction, but is preferably constructed so thatcurrents or jets of air may be caused to issue from openings in itsperiphery or grinding-surface as it rotates, for the purpose of keepingthe grindingsurfaces of the mill cool, and for the further purpose ofassisting in sifting out through the screen-sections of the concave thefine flour and middlings as fast as made. In the drawings I have shown agrinding -cylinder constructed on this principle. It consists of twocircular side plates or flanges, J J, secured to an arbor or shaft, K,and having lands L secured between them, or to their peripheries,apertures at being made in the side plates and spaces a left between thelands, as shown. When the mill is in operation the rapid rotation of thegrinding-cylinder causes air to be drawn in through the apertures minthe side plates and forcibly expelled through the openings or spaces abetween the lands L, thus cooling both the cylinder and the concave, and

assisting in sifting out the fine flour and middlings through thescreen-sections from the materials being ground.

Numerous modifications of the plan of forein g currents or jets of airthrough the periphery of the grinding-cylinder will at once suggestthemselves. For instance, instead of constructing the cylinder withopenings in its sides through which to draw air by the rotation of thecylinder, the arbor or shaft of the cylinder may be made hollow ortubular and divided or provided with openings in the interior of thecylinder, so that air under any desired pressure may be forced into thecylinder through said arbor or shaft, as will be readily understood.

It is evident that instead of adjusting the concave to the stone orgrinding-cylinder, as herein shown and described, the stone orgrinding-cylinder may be so arranged as to be capable of being adjustedto the concave with the same results. The plan of adjusting the concaveis, however, preferable.

The machine may be used to grind middlings or bran or any kind of grain.

I claim as my invention-- 1. In a grinding-mill, the combination,with aconcave provided with alternate grindingsurfaces and screen-sections, ofmeans for adjusting said concave with respect to the face of therotating cylinder or runner, whereby the material can be subjected to areduction .more or less gradual, and the fine flour and middlingsscreened off as fast as made, substantially as described.

2. The combination, with the rotating grinding-cylinder, of theconcavehaving alternate grindingsurfaces and screen sections, and havinginternal partitions between the screensections, whereby the groundproduct passed through each screen-section is kept separate and apartfrom that passed through the other screen-sections, substantially asdescribed.

3. In a grinding-mill, a hollow grindingcylinder consisting of twoperforated side plates or circular flanges secured to an arbor, andlands or grinding-surfaces secured be tween the side plates, or to theirperipheries, with spaces between the lands for the escape of air,substantially as described.

4. In a grinding-mill, the combination of a hollow rotatinggrinding-cylinder,havingopenings in its periphery or grinding-surfacefor the escape of air, with a concave composed of alternategrinding-surfaces and screen-sections, whereby the air escaping from thecylinder assists in bolting the fine fiour and middlings through thescreen-sections of the concave, substantially as described.

WILLIAM N. OOSGROVE.

Witnesses JosEPH G. MOLD, J. H. HARDING.

